Study On Structural System Of Dwelling Houses Made Of CFST Columns And Analysis Of Structural Behavior Of Two New Kinds Of Joints

As one of new composite structures in the field of Civil Engineering, concrete-filled square steel tubular (CFST) structure has high capacity, large energy absorption capacity, and high ductility; also it has regular shape which is easy to connect between columns and beams, convenient fire-control measure and short construction time. Therefore CFST structure will become popular in medium-high rise residential construction. At present time however, critical factors for which extensive applications of CFST structure will be influenced is joint detail scheme. Thus investigation on joints between CFST columns and steel beams in medium-high rise residential construction has significant theoretical and applied value, so has research on reasonable and effective joint detail scheme.To coordinate the promotion of CFST structure and the implementation of new design code, this paper summarizes joint types of concrete-filled square steel tubular column with steel beam according to hinged joints, semi-rigid joints and rigid joints, and simply introduces the present research of the rigid joints. Among the six structural systems that usually be adopted in dwelling structures, the pure frame structure is picked, and on the basis of above analysis and the design of a six-story steel dwelling house, two new types of rigid joint—vertical stiffener joint and diaphragm-through style joint are proposed and a theoretical and experimental study is carried out to understand the mechanical property of these two new types rigid joint.Force transfer mechanism of the vertical stiffener joint model with only tensile beam flange is analyzed. And the results of 3D nonlinear finite element optimization analyses of each type of joints are introduced. Research results suggest that vertical stiffener joint and diaphragm-through style joint model have high capacity and good ductility and that the concrete filled in the tube can increase the yield capacity and stiffness of joints. The formula, which is deduced from theory analysis, is very good to predict the yield capacity of joint model.In order to study the seismic performance of vertical stiffener joint and diaphragm-through style joint, six full-scale cruciform specimens are studied under quasi-static test. The failure process and feature of each specimen are described. Based on the measured hysteresis loops, this paper makes a thorough comparing analysis on the index of seismic behavior such as load-carrying capacity of the joint, ductility, energy dissipation, strength degeneration and rigidity degeneration. The analysis results show that the construction details of vertical stiffener joint and diaphragm-through style joint are simple and reasonable and these two new types of...